A apparatus for controlling pressure in a hydraulic machine

ABSTRACT

Apparatus for controlling the hydraulic pressure in a hydraulic machine, such as a hydraulic press, for enabling the hydraulic pressure to be incrementally increased. A flow control device is provided in the hydraulic circuit of the machine and when the movable member of the machine reaches a predetermined position, it actuates the flow control device. The flow control device initially operates intermittently, with each intermittent operation serving to move a movable member incrementally toward a hydraulic flow blocking position and hence increasing the hydraulic pressure by an incremental amount. Preferably, this is accomplished by an intermittently operated motor which drives a cam that, in turn, moves a valve member toward a flow blocking or closed position. When the hydraulic pressure reaches a preselected amount, the flow control device is operated continuously until the hydraulic pressure reaches a maximum, whereupon no further pressure increase takes place. Once the hydraulic machine has performed its cycle of operations, the flow control device is restored to its original or initial position, ready for a new machine cycle.

i United States Patent [72] lnventor AdolfF.Weiss Easton, Pa.

[Zl] Appl. No. 699,959

[22] Filed Jan. 23, 1968 [45] Patented Jan. 19, 1971 [73] Assignee AlphaPress Company Alpha, NJ.

a corporation of New Jersey [54] APPARATUS FOR CONTROLLING PRESSURE INPrimary Examiner-Everette A. Powell, Jr. Attorney-Roylance, Abrams,Kruger, Berdo & Kaul ABSTRACT: Apparatus for controlling the hydraulicpressure in a hydraulic machine, such as a hydraulic press, for enablingthe hydraulic pressure to be incrementally increased. A flow controldevice is provided in the hydraulic circuit of the machine and when themovable member of the machine reaches a predetermined position, itactuates the flow control device. The flow control device initiallyoperates intermittently, with each intermittent operation sewing to movea movable member incrementally toward a hydraulic flow blocking positionand hence increasing the hydraulic pressure by an incremental amount.Preferably, this is accomplished by an intermittently operated motorwhich drives a cam that, in turn, moves a valve member toward a flowblocking or closed position. When the hydraulic pressure reaches apreselected amount, the flow control device is operated continuouslyuntil the hydraulic pressure reaches a maximum, whereupon no furtherpressure increase takes place. Once the hydraulic machine has performedits cycle of operations, the flow control device is restored to itsoriginal or initial position, ready for a new machine cycle.

,1 Presence SWlTCH v SHEEJLOFZ PATENTEDJANISIHYIA APPARATUS FORCONTROLLING PRESSURE IN A HYDRAULIC MACHINE This invention relates tohydraulic machinery, such as a hydraulic press which includes at leastone punch member movable under the influence of hydraulic pressure andmore particularly, the present invention relates to apparatus forcontrolling the hydraulic pressure within such a machine so that suchpressure can be selectively increased by incremental amounts.

While the present invention is not limited to any particular type ofhydraulic machine, it finds particular utility in connec tion withhydraulic presses of the type which are used for compacting operations.Such presses generally include a pair of relatively movable punchmembers which are movable relatively toward one another to compact apowder or slurry material deposited in the cavity of a die platetherebetween. Ordinarily, such material is supplied in the form of aslurry composed of approximately 50 percent water and 50 percent powder.A commonly used type of powder is ferrite powde r, such as barium. Inone typical type of compacting operation, the bottom punch extendspartially into the cavity in a die plate and the slurry is poured intothe remainder of the cavity. Then, by hydraulic pressure, the upperpunch is lowered into the die cavity to compress and compact the slurrymaterial between the upper and lower punch members. Obviously, in orderto provide a satisfactory final product, some means must be provided forremoving the water which initially forms about half of the slurry. Thecommonly accepted and known way of removing such water was to provide aseries of small drain bores through the bottom punch member and to applya vacuum to these drain bores to tend to draw the water out of theslurry during the compacting operation. It was, however, found that thisprocedure of compacting and water removal was not entirelyysatisfactory.The problem appeared to be in the speed of movement of the upper ormovable punch member. If the punch member was moved at low speed toapply a low initial pressure to the slurry, then the pressure ofcompaction was often offset by leakage in the hydraulic systemitself.That is, at low speeds, the low pressure could not be sustained for anyperiod of time without encountering leakage past the seals in variousvalves. As a result, in such a system it was often not possible to reachthe maximum desired pressure, and as a result, the part or product beingformed was not compacted to a sufficient degree. Alternatively, if anattempt was made to solve this problem by moving the upper punch athigher speeds and greater pressures, thereby overcoming the problem ofleakage in the hydraulic system, it was found that entry of the upperpunch into the die cavity would often tend to force a portion of theslurry out of the cavity. Naturally, in order to make a satisfactorypart, the quantity of slurry or powder material must be accuratelypredetermined, and if even a small portion of this material is forcedout of the cavity, then the remaining material will not have asufficient volume to form a final part of predetermined strengthcharacteristics.

In view of the foregoing considerations, it should be apparent that itwould be desirable to provide means for controlling a hydrauliccompacting press so that the movable member thereof moves slowly atfirst so that the water can be removed from this slurry at low pressure,and thereafter, the speed of the movable member is increased to applymaximum pressure to the part being formed. It is a primary object of thepresent invention to accomplish this beneficial result.

Another object of the present invention is to overcome the difficultiesand deficiencies associated with prior art control devices for hydrauliccompacting presses," and to provide instead, a new and improved methodand apparatus for controlling a compacting press to assure that completewater removal from the slurry can be accomplished without in any waydiminishing the maximum compacting pressure which is ultimately appliedto form the part.

Another object of the present invention is to provide a method andapparatus'for controlling the hydraulic pressure in a hydraulic machineso that such hydraulic pressure can be incrementally increased in acontrolled manner.

Another object of the present invention is to provide a simple andefficient pressure control device for a hydraulic apparatus, such as ahydraulic press.

Another object of the present invention is to provide a method andapparatus for progressively increasing the hydraulic pressure in ahydraulic circuit by incremental amounts until such pressure reaches apreselected amount and thereafter, for continuously increasing thepressure until a predetermined maximum is reached.

Another object of the present invention is to provide a-simple form offlow control device which can be readily installed on any existing typeof hydraulic press, without the need for substantially modifying orrevising such press, and which, when so installed, serves as a controldevice for the hydraulic pressure which operates the press.

Other objects, advantages, and salient features of the present inventionwill be apparent from the following detailed description which, taken inconjunction with the annexed drawings, discloses a preferred embodimentthereof.

The foregoing objects are attained by providing a flow control devicewhich includes a movable valve member interposed in the hydrauliccircuit of a hydraulically operated machine, such as a hydraulic press.A cam member is provided for gradually moving the valve member toward aflow blocking position and as the valve member is so moved, it tends toincrease the pressure in the hydraulic system itself. The cam is drivenby a drive motor which itself is intermittently operated initially inresponse to a signal from the press or machine, such signal beinggenerated responsively to movement of a movable member thereof, such asa punch. As a result, when the motor is operated intermittently, the camis rotated or moved intermittently, and the valve member isintermittentl y advanced toward a flow blocking position. Eachintermittent advance of the valve member causes a corresponding pressureincrease in the hydraulic circuit of the apparatus, and once thepressure reaches a predetermined or preselected amount, then the motoroperates continuously until the valve reaches its maximum flow blockingposition and hence, the pressure in the system reaches a maximum amount.Thereafter, the hydraulic machine performs its cycle of operations, andas such cycle is completed, the motor is once again operated to restorethe flow control device to its initial position, ready for a new cycleof machine operation.

Referring now to the drawings:

FIG. 1 is diagrammatic view, partly in section, showing the basiccomponents of a hydraulic press;

FIG. 2 is a elevational view, partly in section, of a flow controldevice in accordance with the principles of the present invention;

FIG. 3 is a sectional view taken substantially along the line 3-3 ofFIG. 2;

FIG. 4 is a sectional view taken substantially along the line 4-4 ofFIG. 2; and

FIG. 5 is a schematic wiring diagram showing a suitable control circuitfor use with the flow control device of the present invention.

Referring now to the drawings in greater detail, there is shown in FIG.1 the operating portion of a suitable hydraulic machine generallydesignated 10 which is advantageously of the hydraulic press type. Sucha hydraulic machine includes a press table 12 which is normally fixed inposition and which carries an upstanding punch member 14 thereon. Thepunch 14 forms the lower punch in the machine 10. An upper platen 16carries a depending punch member 18, axially aligned with the punchmember 14, and forming the upper punch member for the machine. The upperplaten 16 is supported by an operating rod 20 which can advantageouslybe the piston rod of a hydraulic cylinder and piston arrangementutilized for moving the punch member 18. A lower platen 22 is providedbeneath the press table 12 and is supported by a suitable operating rod24 which again can advantageously form the piston rod of a hydrauliccylinder and piston arrangement. Upstanding rods or support members 26extend from the lower platen 22 through the press table 12 and supportthereupon, a

die case or die plate 28 having a central bore 30 extending therethroughin alignment with the punches l8 and 14, thereby serving to form thecavity for the machine.

As will be apparent, movement of the lower platen 22 causes acorresponding movement of the die case 28. Hence, as the die case 28 ismoved toward or away from the press table 12, the lower punch 14 willmove further into or out of the cavity or bore 30, thereby changing thevolume of this cavity. Thus, by properly adjusting or controlling thedegree of movement of the operating rod 24, the positioning of the diecase 28 will be very precisely controlled, and hence, the volume of thecavity 30 will be accurately predetermined. In my copending applicationSer. No. 649,252, filed June 27, 1967, now U.S. Pat. No. 3,430,538 datedMarch 4, 1969, there is described the method and means for controllingthe movement of the operating rod 24.

Once the die case 28 has been moved or adjusted relatively to the presstable 12 by controlling the degree of movement of the operating rod 24,the volume in the cavity 30 will be determined by the amount of spacebetween the top of the lower punch member 14 and the top of the die case28. This cavity is then filled with a suitable slurry material out ofwhich the article is to be finally formed. Then, by operation of theupper operating rod 20, the upper platen l6 and the punch 18 carriedthereby is lowered toward and into the cavity, to compress and compactthe slurry material therein between the confronting surfaces of therespective punch members 14 and 18. By varying the shape orconfiguration of the punch members, or of the cavity, the shape of thefinal article can be suitably varied. in my copending application Ser.No. 601,791, filed Dec. 14, 1966, now US. Pat. No. 3,407,710, dated Oct.29, 1968, there is described a suitable means for controlling the strokeof the cylinder and piston arrangement which advantageously mounts theupper operating rod 20.

As described hereinbefore, the slurry material which is introduced intothe cavity contains a substantial amount of water and it si necessary todrain this water from the slurry during the compacting operation. Aseries of drain bores 32 are drilled through the lower punch member 14and such bores communicate with a conduit means 34 which can direct theremoved water to a suitable reservoir. While the conduit means 34 canbe, and advantageously is, connected to a suitable vacuum source tospeed the removal of the water from the slurry, it has been found thatthe present invention accomplishes removal of the water from the slurryeven if no vacuum is applied to the conduit means 34.

it will, of course, be understood that the hydraulic machine includes asuitable hydraulic operating circuit and while there are any number ofsuitable types of hydraulic operating circuits which can be utilized forhydraulic presses and hydraulic machines of this general type, thisspecific circuit does not form any part of this invention and hence,need not be described in detail herein. Instead, it is sufficient tostate that the hydraulic operating circuit for the machine 10 includesat least the cylinder and piston arrangement which drives the piston rodfor moving the upper punch and the upper platen. Within this operatingcircuit, a suitable flow control device is provided for the purpose ofaccomplishing the objectives of the present invention and such a flowcontrol device is shown in FIG. 2 and is generally designated 36. Theoperating circuit or wiring diagram forming a part of this flow controldevice, and utilized in conjunction therewith, will be describedhereinafter in connection with FIG. 5. The flow control device 36includes a frame means having a pair of spaced apart support walls 38and 40 joined at one end by an end wall 42. 1f desired, suitableintennediate support columns,

not shown,'-can beprovided betweenthe support walls 38 and to assurethat the same remain fixed in their proper positions.

The flow control device includes a flow valve means generally designated44 which is connected to the end wall 42 by any suitable type ofattachment means. The valve means 44 includes a body 46 having alongitudinal bore 48 extending therethrough and having an angularlyextending bore 50 likewise extending therethrough and intersecting withthe bore 48. A sleeve member 52 is. mounted in the bore 48 to form aseat for a movable valve member 54 having a conical end which seatsagainst the sleeve 52. The valve member 54, as can be seen, is slidablymounted within the bore 48 and is urged toward a closed or seatedposition by a spring member 56.

As aforementioned, the flow control device 36 is interconnected in thehydraulic circuit of the machine and the flow through the valve means 44thereof is in the direction shown by the arrows of FIG. 2. That is, theflow initially enters the bore 48, flows through the sleeve 52 and thenexhausts from the valve through the bore 50. The spring 56 normallyurges the movable valve member 54 toward its closed or flow blockingposition while the flow of hydraulic fluid is in the opposite directiontending to move the valve member 54 away from the sleeve 52 toward itsopen position. Thus, it will be apparent that the stronger the pressureof the spring, the greater the pressure on the hydraulic fluid will haveto be in order for such hydraulic fluid to flow through the valve means44.

An adjustment plunger 58 is mounted within an adjustment nut 60 and theplunger and nut arrangement serve to accurately control the degree ofcompression of the spring 56 and hence controls the force which thespring applies upon the movable valve member 54. An end of the plungerprojects as the rod 62 beyond the nut 60 and hence forms a projectingelement at one end of the valve means 44. At its opposite end, the rod62 carries a forked or bifurcated member 64 which carries an upstandingrod 66 which projects between the forked portions and considerablythereabove. An elongated slot 68 is provided through the support wall 38so that the rod 66 can project therethrough. The roller 70 is rotatablymounted on the rod 66 between the arms of the forked members 64 and ishence aligned with the actuator rod 62 for the valve means 44.

As can be seen from FIG. 2, the slot 68 is elongated suffrciently topermit a considerable degree of lateral movement of the projected rod66. At one end of the slot 68, a switch 72, preferably of the limitswitch type, is mounted so that the plunger 74 thereof is only engagedwhen the rod 66 reaches the end of its travel, at the forward portion ofthe slot 68.

A cam shaft 76 is also provided in the flow control device 36, journaledat its opposite ends in bearings 78 carried respectively by the supportwalls 38 and 40. The cam shaft 76 carries centrally thereupon, aneccentric cam member 80 of a predetermined configuration, one suchsuitable configuration being shown in FIG. 3. At one end, the cam shaft76 is coupled with a drive shaft 82 extending from a gear box 84. Thegear box, in turn, is operated by an impulse driven motor 86 which, inoperation, imparts a rotational movement to the cam shaft 76.

Finally, the cam shaft 76 additionally carries a homing cam 88 which isa segmental type of cam whose configuration can best be seen from FIG.4. Cam 88 is arranged to energize or actuate a limit switch 90 mountedupon the support wall 40 once during each complete rotation of the camshaft 76.

Referring now to FIG. 5, there is shown therein one suitable form ofoperational control circuit or wiring diagram to be utilized inconjunction with the flow control device 36 previously described. Thewiring diagram includes a main on-ofi switch 92 which consists of aganged series of three separate switches 94, 96 and 98. Additionally, itincludes a control relay 100 which operates a pair of ganged switches102, 104. Finally, an adjustable timer means 106 is provided, with such'timer means including an adjustable on cycle and an ad- 75 signalgenerated shortly before the upper punch 18 enters the die cavity30.-Assuming that the main switch 92 in the circuit is in a on"position, as indicated in P10. 5, the signal A is transmitted through awire 110 across the switch 94 and through a wire 112 to thecontrol relay100. Additionally, the signal from thewire 110 is transmitted through aline 114 and across the normally closed switch 116 forming a part of theswitch member 72. The switch 116 is ganged or coupled with a furtherswitch 118 whose function will be presently described. As the currentcontinues across the switch 116 and alongthe line 114, it is supplied tothe timer 106 and also to a blue control signal light 120. This signallight indicates that power is being supplied to the timer and thecontrol relay.

As briefly mentioned hereinabove, the timer is provided with both anadjustable "on and an adjustable off cycle. Preferably, each of thesecycles is adjustable between 0 and seconds and if it assumed that eachcycle isadjusted to 5 seconds, then the timer, will be "off for 5seconds, then "on" for 5 seconds, then off. again for 5 seconds, and soon in an intermittent manner. One suitable formof timer of this type issold commercially by Timeco, lncl'of Huntington, West Virginia, underthe designation Model 04.

When the timer 106 switches to its .on cycle it closes the switch 122associated therewith and supplies current through a line 124 to themotor 86. it simultaneously energizes a green control signal light 126.As previously explained, operation of the motor 86 rotates the cam shaft76 and hence rotates the earns 80 and 88 carried thereby. The motor 86will only operate so long as the timer 106 is -in.its"on" cycle, sinceas soon as the timer is switched to its off cycle, the switch 122 ismoved from its closed position to its open position as shown v in FIG.5. Thus, it' will bev understood that the motor 86 is operated in anintermittent manner and tliat the shaft 76 is thus rotatedintermittently thereby advancing the earns 80 and 88 intermittent. Asthe cam 80 rotates in an intermittent fashion it contacts the roller 70and applies a pressure thereto which pushes on the shaft 62 and therebyincreases the pressure of the spring 56.- Since the spring pressure onthe movable valvemember 54 is increased, the pressure in the hydrauliccircuit of the machine is necessarily increased since it becomes moreand more difficult to open the valve 54 to permit the flow from theconduit 48 to the conduit 50. As the pressure in the hydraulic circuitincreases, the pressing force applied to the slurry contained within thecavity is also increased, with such increase being small increments.

Again as shown in FIG. 1, an adjustable pressure switch 128 is providedin association with the machine hydraulic circuit, and in particular,with the hydraulic cylinder and piston arrangement which moves thepunch-member 18. This pressure switch can be adjusted to anypredetermined amount,. and when the pressure has been incrementallyincreased to this amount, a signal B is generated. As shown in F IG. 5,this signal B comes across a line 130, across the switch 96 and acrossthe normally closed switch 118 forming 'a part of the switch means 92.The control relay 100 will have closed the switch 102 against thecontact 132 in response to the signal A which had previously receivedand hence the current supplied along the line 30 can continue across theswitch 102 and across a line 134 to the timer switch 122. From there,the current flows across the closed timer switch 122 and-through theline 124 to the motor 86 to cause the same to drive continuously. Thiscontinuous driving will take placeuntil the high spot on the cam 80contacts the roller 70. At; this time, the forked assembly 64 and theroller 70 will be advanced their maximum position toward the valve means44 and the rod 66 will be ad-' vanced in theslot 68 untilit contacts theplunger 74 of the switch 72. At this time, the normally closed switches116 and 118 which comprise the switch 72 will be opened and current tothe motor 86 will be interrupted. At this time, the maximum pressurewill be exerted in the hydraulic circuit, although, if desired, aseparate force adjusting valve, not shown, can be provided in thecircuit so that the circuit pressure will never exceed a maximumpreselected amount.

It will be understood from the manner of operation set forth thus farthat punch 18 enters the die cavity at a low pressure. This pressure isthen incrementally increased until a preselected value is reachedwhereupon the pressure is thereafter increased continuously until apreselected maximum is reached. The incremental pressure increase servesto compress the slurry to remove the water therefrom and the maximumpressure applied continuously is utilized for forming the part betweenthe punches 14 and 18 Once the compacting operation has been completed,and the punch 18 and platen 16 are raised, the signal A is shut off.When this occurs, the control relay resets to the position shown in FIG.5. Additionally, constant voltage C either from the machine or from somesuitable external source is applied across a wire 136, through a wire138, across a normally closed switch forming one of two switches in theswitch means 90 and across the wire 142 to the normally closed switch104 in the control relay. This current then flows-from the switch 104through a line 144,.through the "on switch 98 and through a line 146which connects with the line 124. As a result, this constant voltagefeeds back through the line 124 to the motor 86 to drive the samecontinuously until the cam 88 contacts the switch 90. While this isoccurring, a portion of the current from the line 138 feeds across theother switch 148 forming a part of the switch means 90 to energize a redcontrol light which indicates that the apparatus is returning to itshome" position. When the cam 88 contacts the switch 90, the home"position is reached and the switches 140 and 148 are opened. This cutsoff all current to the motor 86, and at this time, both of the cams willhave been returned to their initial position, all of the circuitcomponents will have been returned to their initial positions, thepunches will have been returned to their initial positions, and theentire apparatus will be ready for a new machine cycle.

If the flow control device selector switch 92 is moved to a offposition, then all of the switches 94, 96 and 98 will be moved fromtheir on" positions, as shown in FIG. 5 to a of position and the circuitwill operate in the following manner.

.The current feeding through the line 1306 will be transmitted through abranch line 152 to the' of "terminal for the switch 98. Since the switch98 will be in the off position, the current will feed through the switch98 through the line 146 and back through the line 124 to operate themotor 86. The motor will rotate the cam shaft and the cam 80 until thehigh spot on the cam causes the operating rod 66 to energize the switch72. At this time, theindividual switches l 16 and 1 18, which comprisethe switch means 72, will be opened and the entire control unit 36 willbe taken out of operations so that it does not interfere with the mainmachine. Of course, when it is desired to place the pressure controlunit 36 back into operation in the system, one need only to turn theswitch means 92 from its of position to its on" position.

It should be apparent after reading the foregoing detailed descriptionthat the present invention provides a unique method and means forenabling the movable punch member to be introduced into the cavity atlow pressure, with the pressure thereafter being progressively increasedby small incremental amounts. In practice, it has been found thatincremental pressure increases of between 5 and 10 p.s.i. providessatisfactory results. These incremental pressure increases will serve toremove the water from the slurry and exhaust the same through the drainconduit 34, even if no vacuum is applied to this conduit. Of course, avacuum can be used, if desired, since this will merely speed up theoperation of extracting the water from the slurry. When a preselectedamount of pressure has been applied incrementally, the system willoperate continuously to increase the pressure to a predetermined maximumamount. This maximum pressure is utilized for compacting the slurrywithin the cavity for forming a final part of desired strengthcharacteristics.

While the invention described in the foregoing detailed description andshown in the appended drawings, which form a part of this specification,accomplishes the objectives set forth at the outset hereof, it will beunderstood that various other changes and modifications can be madewithout departing from the scope of the invention as defined in theappended claims.

lclaim:

1. In a fluid operated apparatus which includes at least one movablemember and a fluid pressure system which applies pressure to said memberto effect the movement thereof, the improvement for enabling said memberto be moved both incrementally and continuously, as selected, whichcomprises:

flow control means in said fluid pressure system;

said flow control means including at least one movable portion movabletoward a flow blocking position;

movable force applying means for operatively engaging said movableportion;

drive means for moving said movable force applying means;

drive control means responsive to a signal generated pursuant tomovement of said movable member for intermittently actuating said drivemeans;

said drive means thus intermittently moving said movable force applyingmember which in turn intermittently moves said movable portion towardsaid flow blocking position; and

each intermittent movement of said movable portion toward said flowblocking position correspondingly increasing the pressure in said fluidpressure system, thereby causing said pressure to increase inprogressive increments.

2. The improvement defined in claim 1 wherein said movable forceapplying means includes a cam member and wherein said drive meansincludes a motor for moving saidcam member.

3. The improvement defined in claim 2 further including first switchmeans and switch actuating means coupled with said movable portion, saidswitch actuating means engaging said first switch means when said camdisplaces said movable member its maximum degree of movement.

4. The improvement defined in claim 3 wherein said first switch means isoperatively coupled with said motor and wherein, when said first switchmeans is actuated by said switch actuating means, said motor is drivencontinuously until the fluid pressure in said system reaches apredetermined maximum amount.

5. The improvement defined in claim 4 further including second switchmeans and segmental cam means operated by said motor to engage saidsecond switch means when said cam member reaches its initial position,thereby restoring said How control means, drive means and drive controlmeans to their initial positions, ready for a new cycle of operations.

6. In a fluid operated apparatus which includes at least one movablemember, a fluid pressure system which applies pressure to said member toeffect movement thereof, and a flow control means in said fluid pressuresystem, the improvement for enabling said member to be moved bothincrementally and continuously, as selected, which comprises:

a flow line in said fluid pressure system having a valve seat therein;

movable valve means in said flow line, including a valve member andbiasing means urging said valve member toward said valve seat to blockflow through said flow line;

said movable valve means also including a projecting plunger operativelyengaged with said biasing means;

a rotatable shaft having a cam member thereon, said can] member beingengageable with said plunger as said shaft rotates;

drive motor means for rotating said shaft;

drive motor control means operable responsively to a signal generatedpursuant to movement of said movable member for intermittently operatingsaid drive motor and hence for intermittently rotating said shaft andsaid cam member; and said cam member rotation engaging said cam memberagainst said plunger so that each intermittent cam rotation causes saidplunger and hence said valve member to move toward said valve seat,thereby causing the pressure in said fluid pressure system to increasein progressive increments.

7. The improvement defined in claim 6 further including first switchmeans operatively coupled with said drive motor and a switch actuatingelement projecting from said plunger to engage said first switch meanswhen said cam member moves said plunger its maximum degree of movementtoward said valve seat, said first switch means, when engaged by saidactuating element, causing said drive motor to drive continuously untilsaid fluid pressure in said system reaches a predetermined maximumamount.

1. In a fluid operated apparatus which includes at least one movablemember and a fluid pressure system which applies pressure to said memberto effect the movement thereof, the improvement for enabling said memberto be moved both incrementally and continuously, as selected, whichcomprises: flow control means in said fluid pressure system; said flowcontrol means including at least one movable portion movable toward aflow blocking position; movable force applying means for operativelyengaging said movable portion; drive means for moving said movable forceapplying means; drive control means responsive to a signal generatedpursuant to movement of said movable member for intermittently actuatingsaid drive means; said drive means thus intermittently moving saidmovable force applying member which in turn intermittently moves saidmovable portion toward said flow blocking position; and eachintermittent movement of said movable portion toward said flow blockingposition correspondingly increasing the pressure in said fluid pressuresystem, thereby causing said pressure to increase in progressiveincrements.
 2. The improvement defined in claim 1 wherein said movableforce applying means includes a cam member and wherein said drive meansincludes a motor for moving said cam member.
 3. The improvement definedin claim 2 further including first switch means and switch actuatingmeans coupled with said movable portion, said switch actuating meansengaging said first switch means when said cam displaces said movablemember its maximum degree of movement.
 4. The improvement defined inclaim 3 wherein said first switch means is operatively coupled with saidmotor and wherein, when said first switch means is actuated by saidswitch actuating means, said motor is driven continuously until thefluid pressure in said system reaches a predetermined maximum amount. 5.The improvement defined in claim 4 further including second switch meansand segmental cam means operated by said motor to engage said secondswitch means when said cam member reaches its initial position, therebyrestoring said flow control means, drive means and drive control meansto their initial positions, ready for a new cycle of operations.
 6. In afluid operated apparatus which includes at least one movable member, afluid pressure system which applies pressure to said member to effectmovement thereof, and a flow control means in said fluid pressuresystem, the improvement for enabling said member to be moved bothincrementally and continuously, as selected, which comprises: a flowline in said fluid pressure system having a valve seat therein; movablevalve means in said flow line, including a valve member and biasingmeans urging said valve member toward said valve seat to block flowthrough said flow line; said movable valve means also including aprojecting plunger operatively engaged with said biasing means; arotatable shaft having a cam member thereon, said cam member beingengageable with said plunger as said shaft rotates; drive motor meansfor rotating said shaft; drive motor control means operable responsivelyto a signal generated pursuant to movement of said movable member forintermittently operating said drive motor and hence for intermittentlyrotating said shaft and said cam member; and said cam member rotationengaging said cam member against said plunger so that each intermittentcam rotation causes said plunger and hence said valve member to movetoward said valve seat, thereby causing the pressure in said fluidpressure system to increase in progressive increments.
 7. Theimprovement defined in claim 6 further including first switch meansoperatively coupled with said drive motor and a switch actuating elementprojecting from said plunger to engage said first switch means when saidcam member moves said plunger its maximum degree of movement toward saidvalve seat, said first switch means, when engaged by said actuatingelement, causing said drive motor to drive continuously until said fluidpressure in said system reaches a predetermined maximum amount.